Communication systems, and wireless communication systems in particular, have been under extensive development in recent years. In addition to the conventional speech transmission, several new services have been developed. Different data and multimedia services are attractive to users, and communication systems should provide sufficient quality of service.
In addition to new services, the number of different technologies in the area of wireless communication has increased. In addition to cellular communication systems, such as GSM (Global System for Mobile Communication) and UMTS (Universal Mobile Telephone System), local area networks such as WLAN (Wireless Local Area Network) and WiMAX (Worldwide Interoperability for Microwave Access) have been developed, for example.
To provide users with good and versatile service, manufactures have introduced communication devices which support several different networks and radio access systems. The devices may be configured to maintain several service connections simultaneously. For example, a speech call may be ongoing while the device is connected to the Internet using an Internet Protocol based connection.
As users of mobile communication units move, the mobile units with ongoing service connections may be transferred in a handover procedure from one base station or network element to another one which offers better signal quality, capacity or other capabilities to support service connections. With the introduction of networks with a variety of different capabilities and capacities the present methods of performing handover may lead to problems in the quality of service experienced by the users.